1. Field of the Invention
This invention relates to a holographic stereogram printing or formulating system for producing a holographic stereogram that is able to recognize an actually imaged picture or a computer-generated picture three-dimensionally.
2. Description of the Related Art
A holographic stereogram is formulated by sequentially recording a large number of pictures, obtained on sequentially imaging an object from different viewing points, as original pictures, on a sole holographic recording medium, in the form of strip-shaped or dot-shaped element holograms.
In the case of a holographic stereogram having the parallax information only in the horizontal direction, for example, plural original pictures 101a to 101e, obtained on sequentially imaging an object from different viewing points in the horizontal direction, are sequentially recorded on a holographic recording medium 102 in the form of strip-shaped element holograms.
If the holographic stereogram is viewed with one eye from a given position, a two-dimensional picture, as a set of the picture information of a portion of the respective element holograms, is viewed, whereas, if it the eye position is moved in the horizontal direction, a two-dimensional picture, as a set of the picture information of another portion of the respective element holograms, is viewed. Thus, if a viewer observes the holographic stereogram with both eyes, the two-dimensional pictures as seen by the left and right eyes differ slightly from each other because of the slight difference in the positions of the left and right eyes in the horizontal direction. Thus, the viewer feels the parallax, with the reproduced picture being recognized as a three-dimensional picture.
Meanwhile, in formulating a hologram of high picture quality, it is known to be effective to place a diffusion plate in the vicinity of picture displaying means. Among reference materials, there are "Endo and Yamaguchi et al, 23rd Picture optical Conference 1992 p 317 ff" and "Michael Klug et al, 1993 proc SPIE#1914 Practical Holography VII,".
However, if a diffusion plate is arrayed in the vicinity of the picture display means, there is observed a nonuniform noise at an infinitely remote position in the produced hologram. Attempts to move the diffusion plate to reduce the noise is proposed in Japanese Laying-Open Patent 8-1722382. However, if there are a number of movement units, there is raised a problem in connection with vibration resistance. If the diffusion plate is used, the light utilization efficiency is lowered.